Smith out, Kaepernick to start for 49ers

San Francisco 49ers quarterback Colin Kaepernick (7) throws the ball against the St. Louis Rams during the third quarter at Candlestick Park. The San Francisco 49ers tied the St. Louis Rams 24-24. (PHOTO: US PRESSWIRE)

Monday night's contest between the Chicago Bears and San Francisco 49ers will be a battle of backup quarterbacks.

The Bears had already rules out concussed quarterback Jay Cutler in favor of Jason Campbell. And San Francisco's Alex Smith failed to receive clearance to play today after suffering his own concussion in Week 10, meaning his run of 28 consecutive starts (including playoffs) will end.

ESPN's Chris Mortensen first reported the development.

Second-year signal caller Colin Kaepernick will make his first pro start for San Francisco.

Though inexperienced, Kaepernick's big arm and ability to tuck and run will change the complexion of the Niners offense, which has used the 2011 second-round pick in specialty packages this season. The Bears defense may be more hard pressed to adapt to the new look than the 49ers, who will deal with the pocket-bound Campbell.

No. 2 quarterbacks didn't fare all that well Sunday. Philadelphia's Nick Foles and Pittsburgh's Byron Leftwich were largely ineffective in defeat while making their first starts of 2012. Arizona's Ryan Lindley, Kansas City's Brady Quinn and Jacksonville's Chad Henne were unable to lead their teams to victory after taking over yesterday, though Henne (354 yards, 4 TDs) was spectacular in relief of injured Blaine Gabbert.

But someone will score a win for the clipboard fraternity tonight ... assuming the 49ers can avoid another tie, of course.